The workers were convicted on charges of disturbing public order following their participation in a protest on May 1, during which they called for better working conditions and better wages.
The convicts have 20 days to appeal the sentence.
Radio Farda reports that in recent months, a number of Iranian workers calling for better rights have been harassed, detained, or jailed.
RFE/RL Iran Report
SUBSCRIBE For regular news and analysis on Iran by e-mail, subscribe to "RFE/RL Iran Report."